Portable oxygen concentrator



FIG. 1 is a front-right-top perspective view thereof;

FIG. 2 is a back view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a left view thereof;

FIG. 5 is a right view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines in FIGS. 1 to 7 are included for the purpose of illustrating portions of the portable oxygen concentrator that form no part of the claimed design. 

The ornamental design for a portable oxygen concentrator, as shown and described. 